Related art pertinent to warming articles making use of heat generation accompanying oxidation of an oxidizable metal with oxygen in air includes the warming tool described in JP-A-2003-332.
The warming tool comprises a cap-shaped base sheet which is adapted to be put on the head and a plurality of heat generating elements attached to the base sheet. The heat generating element of the warming tool loses flexibility and gets rough to the touch due to caking of the heat generating powder. Therefore, a warming article that is soft to the touch, conformable to a body, and useful in various applications has been awaited.
Related art pertinent to heat generating sheets utilizing heat generation accompanying oxidation of an oxidizable metal powder with oxygen in air includes the heat generating sheet disclosed in Japanese Patent No. 2572621. The sheet is produced by a papermaking technique using a composition of iron powder, activated carbon, an electrolyte, water, and a fibrous substance.
Applicant previously proposed a thin, heat generating molded article in JP-A-2003-102761. One of the characteristics of the molded article lies in that it is extremely thin and yet exhibits excellent heat generating characteristics as a heat generating element.
Separately from these heat generating elements of sheet form, heat generating shaped articles having a three-dimensional shape are desired in some applications. JP-T-1999-508786 proposes a three-dimensionally shaped heat generating element. Because the heat generating element is a heat cell having a given shape filled with an exothermic powder, it is difficult to obtain a three-dimensional shape appropriate for a specific application. Moreover, the technique requires a large quantity of the exothermic powder for obtaining desired heat generating performance and involves complicated steps for the production.